Hello Michal,
No NX-OS additional License is required for vPCs. Although the IP tunnels do require additional licensing, for further information refer to:
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/licensing/guide/b_Cisco_NX-OS_Licensing_Guide/b_Cisco_NX-OS_Licensing_Guide_chapter_01.html
I believe there is a mistake in the sentence from the 2nd link.
Best Regards!